pfc on 3 phases

[john h owen]

when prospective fault testing a three phase circuit do you only need to do the short circuit test only on the 3 phases in turn due to result being twice that of the earth short circuit current due to the line voltage being twice the value?

 

[Spa Key]

when prospective fault testing a three phase circuit do you only need to do the short circuit test only on the 3 phases in turn due to result being twice that of the earth short circuit current due to the line voltage being twice the value?

First of all, short circuit = L-N. Earth fault = L-E. You're on the right track though, take the highest PFC and double it.

 

[Sintra]

when prospective fault testing a three phase circuit do you only need to do the short circuit test only on the 3 phases in turn due to result being twice that of the earth short circuit current due to the line voltage being twice the value?

Personally on a 3 phase i only test between phases for PFC as it has to be the highest and don't worry about the L - E & L - N single phase readings.

 

[Risteard]

Same here. My meter can test directly between phases. However if I was using a meter that couldn't then I would just test each phase to neutral and double the highest result. I ignore PEFC as PSCC must be higher in a three-phase system.